As I look at the photos in that link, at the top where the ring was pressed into the person's arm, they are slightly indented (almost like the smallpox vaccinations we baby-boomers all have on our upper arms). You younger posters can ask to see your parents' smallpox marks.
Actually, I don't think those indented marks look anything like the marks on JBR. For one thing, the marks on JBR are very much darker, almost like a burn. I disagree with the coroner's description of them as "abrasions". Abrasions, to me, are more like scrapes. And the darker appearance is not because she is dead. If it were livor mortis causing the darker appearance, the marks would be deep red, not those brownish purple marks.
I do, however, see how the stone pattern in the ring could possibly be what we see inside the mark. I just think a ring would have to be pressed deliberately very hard to make a mark like that, though I suppose if the person tightening the garrote was also wearing the ring...but I am having difficulty picturing how the hands would be positioned if tightening the garrote and pressing the ring into her skin at the same time.
I also read about the potholder loom, and saw the pics of the loom on her nightstand. I believe the scattered hairties were actually the fabric loops used to make the potholder. My daughter had one of those looms years ago, and we actually did use some of the loops on her hair once in awhile when we couldn't find a coated elastic. This was before there were "scrunchies".